In Aldous Huxley's "Brave New World," the World State divides people into Alpha, Beta, Gamma, Delta and Epsilon castes. These castes define the role a person has in society, the work they perform and how they compare to people in other castes.
The World State developed the caste system to enforce its guiding motto: “Community, Identity, Stability.” It named castes using the first five letters of the Greek alphabet, which also correspond to grades equivalent to A, B, C, D and F. The Alpha caste is intellectually and physically superior to all other castes, betas are second-best, Gammas are third-best, Deltas are fourth-best and Epsilons are fifth-best, created to perform menial labor.
The Hatchery mostly leaves the Alpha and Beta embryos and fetuses untouched but deprives the other three castes of oxygen and treats them with chemicals during gestation. Gammas, Deltas and Epsilons also undergo the Bokanovsky Process, which causes one egg to divide and form up to 96 identical embryos, which in turn become 96 identical people predestined for identical tasks. The World State believes this creates stability and results in people who accept and love their lot in life.
Conditioning also continues after birth. For example, Delta infants are programmed to dislike books and flowers, which makes them more docile and eager consumers. This conditioning takes away their choices, prevents anarchy and uprisings, and makes it virtually impossible for them to perform any task other than the one assigned at birth and by their caste.